Abstract accepted for IOUG...company has no/little money to send me?!??!?!?!

So I got the word from IOUG that my abstract has been accepted.
Hurray!!

I forwarded that acceptance email to my manager asking for some travel
money, and state the obvious that I won't need any money to pay for the
conference fee.

I eventually get a response back from his manager that the overhead
money is tight...maybe we can send you for a day or two...??!?!?!??!?!
Overhead money is tight? Isn't it January?

So that was yesterday, and today I have calmed down a bit. And I was
wondering if other folks have encountered this problem? Wondering if
this is common? I have always assumed that if you get accepted to
present then your company "stepped up" and sent you. I guess I am
wrong?